Math question help?

0 = -110 + (1 / (1 + r)) * (32.1 / r)
110 = 32.1 / (r² + r)
110r² + 110r - 32.1 = 0

This is a quadratic equation which can be solved by the formula:
x1 = (-b + (sqrt (b² - 4ac))) / 2a
x2 = (-b - (sqrt (b² - 4ac))) / 2a

In the given problem the values are:

a = 110
b = 110
c = -32.1

The discriminant D = b² - 4ac evaluates to:
D = 110² - 4 * 110 * -32.1 = 26224

If D > 0 , there are 2 solutions in R (set of real numbers).
If D = 0 , there is 1 solution in R (set of real numbers).
If D < 0 , there are 0 solutions in R (set of real numbers).

The two solutions are:
x1 = (-110 + (sqrt (26224))) / 220
x2 = (-110 - (sqrt (26224))) / 220

x1 = 0.2361
x2 = -1.2361

I have not the slightest idea, what IRR finance problems are, so you have to decide on your own, whether the negative solution is nonsensical in this context or not.

On quadratic equations consult e. g. :
https://en.wikipedia.org/wiki/Quadratic_formula